Soy intake is associated with lowering blood pressure in adults: A systematic review and meta-analysis of randomized double-blind placebo-controlled trials

Background: Soy has several beneficial effects on cardiovascular disease (CVD); however, results of clinical trial studies are equivocal. Thus, the present study sought to discern the efficacy of soy intake on blood pressure. Methods: The search process was conducted in PubMed, Scopus, Web of Science, and Cochrane Library, to ascertain studies investigating the efficacy of soy intake on blood pressure in adults, published up to June 2020. A random-effects model was applied to pool mean difference and 95 % confidence interval (CI). Begg's and Egger's methods were conducted to assess publication bias. Results: Pooled effects from 17 effect sizes revealed a significant improvement in systolic blood pressure (SBP) (−1.70; −3.34 to −0.06 mmHg; I ² = 45.4 %) and diastolic blood pressure (DBP) (−1.27; −2.36 to −0.19 mmHg, I ² = 43.9 %) following soy consumption, in comparison with controls. Subgroup analysis demonstrated a reduction in both SBP and DBP in younger participants with lower baseline DBP and intervention durations of <16 weeks. Conclusion: Our results suggest that soy intake is associated with an ameliorating effect on blood pressure in adults.